In many gear systems or gear trains, meshed gear teeth have end bearing faces which abut against smooth flat faces or surfaces of a surrounding structure, such as housing walls forming a gear chamber. The end faces of the gears and the faces of the housing are extremely smooth and flat and encounter thrust loads normal thereto.
Most such gear systems are lubricated by a fluid and it is desirable for the lubricating fluid to enter the spaces between the end bearing faces of the gears and the adjacent flat bearing faces or surfaces of the housing. The fluid is intended to form a hydromechanical fluid bearing film between the faces. However unfortunate, the fluid bearing film tends to be squeezed out in a thrust loading situation where thrust loads are encountered normal to the bearing faces. In addition, the faces often experience smooth metal surface adhesion, sometimes termed "joe-blocking". This is particularly true when the gears are provided with ultra-smooth end bearing faces.
The invention is directed to solving the above problems by providing a micro-contoured surface on the end bearing faces of the gears to facilitate the intrusion of lubricating fluid between the gear and housing surfaces.